Objective is when ever Telephone Set goes off hook , controller detects off hook and sents a Dial Tone to the telephone set for 20 Seconds and after 20 seconds program END.  Using 12 MHz Crystal.  Firstly the Program do nothing untill a logical high signal comes at P1.0.  When a Logical high Signal somes at P1.0,  Timer 0 interrupt comes in act  1000 Hz square wave is produced at P2.0.  Now how I can make controller to sent this upto 20 seconds and,  After that sents a Busy TONE type of Sound by generating the same square wave but with 0.1 second ON and 0.1 Second OFF. ORG 00H LJMP MAIN ORG 000BH CPL P2.0 RETI MAIN: JNB P1.0,$ JMP DIAL TONE DIAL TONE: MOV TMOD,#20H MOV TH0,,#-50 SETB TR0 MOV IE,#82H Upto 20 seconds DIAL TONE and after that BUSY TONE keeps on going. END
Nver mind ,i have solvd my problem thank u 4 ur help
Nver mind ,i have solvd my problem thank u 4 ur help You just saved 10 seconds typing in stupid SMS and made everyone trying to read your post spend 30 seconds trying to decipher it. Erik